Metering device for the inhalation of a pulverulent substance

ABSTRACT

A metering device can be activated by a suction airflow of a user for inhaling a powdery substance, in particular of medicinal type, which is arranged in a supply chamber and can be brought out of there into an apparent discharge standby position by removing a mouthpiece sealing cap by a metering chamber of a metering rod. The metering device provides piston-extensible tabs for sealing off the metering chamber, particularly for the facilitated opening of the metering chamber.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a metering device which can be activated by theuser's suction airstream and is intended for the inhalation of apulverulent substance, in particular a medicinal substance, according tothe preamble of the main claim.

A metering device of the type in question is known from WO 2006/021546A1. The quantity of substance separated off in the metering chamber ismoved into a closed emptying-standby position. As a result of a userbreathing in, a piston moves and opens the metering chamber. Thereafter,the latter is connected to an air-flow path for clearing theseparated-off quantity of substance out of the metering chamber andtransferring it into the airstream which is to be sucked in.

In view of the known prior art, it may be considered to be a technicalproblem of the invention to develop in an advantageous manner a meteringdevice of the type in question in respect of the inhalation operation,in particular in respect of the movement of the piston into theemptying-release position.

BRIEF SUMMARY OF THE INVENTION

This problem is substantially solved by the fact that the piston, whichis of disk-like configuration in the upper region, is provided withtongues which extend from the underside of the disk, close the meteringchamber in the emptying-standby position and release the meteringchamber when the piston is displaced by the user's suction airstream.This configuration gives a space-saving solution which, in terms of thepiston configuration, saves weight and runs smoothly. The piston isminimized in terms of its functional portions and, correspondingly, hasa piston surface which is used for displacing the piston, and also hastongues which cover over the metering chamber in the emptying-standbyposition. The piston disk is preferably formed more or less as a planarcomponent or, in a further configuration, in the manner of a dished capwith the opening of the dish directed away from the piston-activationsurface. The piston disk here has a material or wall thickness which issufficient to ensure sufficient inherent stability of the disk, thus,for example, 0.5-2 mm, furthermore, for example, 1 mm. The tongues areformed integrally, and in a single unit, with this piston disk. Theyextend, on both sides of a central piston axis, form thepiston-activation surface. The tongues here may also be ofcross-sectionally rectangular configuration, with a cross-sectionallength corresponding to a multiple of the cross-sectional width. As analternative, it is also possible for the tongues to be cross-sectionallyconfigured in the manner of circle segments, with a flat side associatedwith the metering chamber. The configuration selected for the pistonmeans that only a relatively low mass needs to be shifted when thepiston is displaced, but a large-area engagement surface is provided,and this makes it easier for the piston to be moved out of theemptying-standby position into the emptying-release position by means ofthe user's suction airstream. Accordingly, only a relatively low levelof suction airstream energy is required in order to release the meteringchamber. Furthermore, the narrow construction of the piston makes itpossible to achieve increased levels of air energy during inhalation. Itis also possible for a plurality of metering chambers to be coveredover, without increased levels of friction, as a result of the narrowtongues. The metering rod can also easily be exchanged at any time, forexample for adaptation to a dose of substance.

In an advantageous development, it is provided that, in its upper endposition, the upper periphery of the piston engages in front of anannular wall, which belongs to an annular chamber, and preferably theceiling of the latter has peripherally extending, projecting wings whichleave intermediate spaces between them. Disposed downstream of the sameis a ceiling portion which constitutes an oblique deflecting wall withconcentrating action. Further preferably, the piston, which has airflowing around it during inhalation, i.e. during suction-air activationby the user, releases the path to an annular chamber in the upperposition, i.e. in the emptying-release position of the metering chamber.The powder which is to be inhaled consists, for example, of a basicbody, such as lactose, which can be transported by a suction stream andis suitable as a carrier for fine micronized drug particles adhering toits surface. The powder-laden suction air is extracted by suctionthrough intermediate spaces which are formed between the wings extendingradially outward from the cover and from where the suction air passes,in slightly concentrated form, into the mouthpiece of the meteringdevice. A further, space-saving solution is achieved by the latchinghead of the metering rod being partially sunken into the upperdepression of the disk piston, the latching head being sunken into theabovementioned dish-like hollow of the piston. The metering rod isretained in an inner cylinder, which can be rotated by the closure cap,such that it can be displaced along the axial extent of the innercylinder. The rotation of the inner cylinder is transmitted to themetering rod. This inner cylinder is provided, on the lateral-wall side,with an axially running channel which extends from the emptying side ofthe metering chamber and terminates in the annular chamber, it beingpossible for the deflecting-wall wing to be provided in order to deflectthe axial airstream direction into the orbital plane. Accordingly, thisdeflecting-wall wing is disposed in the manner of a cover in axialextension of the channel, with the radial outlet being left in theprocess. Via this channel, following the suction-air-induced raisingoperation of the piston and the associated release of the meteringchamber, the separated-off dose of substance is sucked out and fed, viaan annular chamber, to the user who is building up the suctionairstream. Conventional suction in the radial direction out of themetering chamber gives rise, in first instance, to deflection into theaxially running channel, this being correspondingly associated with abaffle-plate action for breaking up coarse powder particles. In apreferred configuration, deflection from the radial flow direction intothe axial flow direction is achieved by two channel deflection regionswhich are located directly one after the other and each cause flow to bedeflected by 45 degrees. An intermediate channel portion which runs atan angle of approximately 45 degrees to a plane oriented transversely tothe axis of the device, and connects the emptying side of the meteringchamber to the axially running channel, is thus also preferablyprovided.

Along their lower free periphery, the tongues are split in a lip-likemanner in order to achieve a clamping action in interaction with themetering rod, and/or for sealing interaction with a sealing seat.Furthermore, the tongues have material-reinforced sealing surfaces, forclosing the metering chamber on both sides in the emptying-standbyposition. Following displacement of the metering rod with the meteringchamber into the emptying-standby position, it is possible for theclosure cap to be screwed on again without any adverse effects, even ifinhalation has not been carried out, and this results in the returndisplacement of the metering rod. Since only the sealing surfaces, whichinteract with the metering chamber, are material-reinforced, the rest ofthe axial portions of the tongues, as seen in cross-section, are spacedapart from the associated wide surface of the metering rod by the extentof the material reinforcement. This configuration minimizes thefrictional forces of the piston with the tongues during thesuction-air-induced axial displacement. A sucking-in flow channel, whichis directed toward one of the two tongues, constitutes a visual checkfor visually checking whether the rod is located in the removal-standbyposition.

The substance which is to be inhaled is stored in a storage chamber,into which the metering chamber penetrates for filling purposes. Inorder to assist the filling operation of the metering chamber here, andfurthermore to achieve the situation where the uppermost layer of thesubstance store, which has the metering chamber passing through it, isalways loosened, a rotor-like blade is mounted on the lower periphery ofthe inner cylinder, for example clipped thereon, which blade interactswith an inwardly directed stator-like shoulder of the storage-chamberwall. This allows the replenishment and the density of the substance inthe storage chamber to be kept constant. Added to this is a looseningeffect which is provided in the area surrounding the metering chamberand prevents fractions of the substance from coming to a halt.Furthermore, the rotor, in interaction with the stator, is configuredsuch that, when the rotor-like blades are moved back when the closurecap is replaced and screwed on and the metering chamber is lowered intothe storage chamber, the uppermost substance layer is subjected toslight contact pressure, in order thus to provide, in the storagechamber, an evened-out uppermost substance-quantity region associatedwith the metering chamber. This results in the metering chamber having afilling which can be reliably enclosed by the tongues.

Finally, it has also proven to be advantageous to provide, in the regionof the storage-chamber wall, a filling-level indicator which makes itpossible to ascertain the amount of filling. In the simplestconfiguration, this can be coupled directly to the axial movement of apressure piston which is disposed in the storage chamber and subjectsthe stored quantity of substance to loading from beneath in thedirection of the inner cylinder. This pressure piston advances assubstance is removed, and this can be observed via the filling-levelindicator.

The invention is explained in more detail hereinbelow with reference tothe accompanying drawing, which merely constitutes an exemplaryembodiment and in which:

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 shows the vertical section through a metering device according tothe invention in the basic position, with the cap closed;

FIG. 2 shows a further vertical section along line II-II in FIG. 1;

FIG. 3 shows an enlargement of an upper region of the device accordingto FIG. 1;

FIG. 4 shows a sectional illustration corresponding to FIG. 1, relatingto the situation where the storage chamber for the substance which is tobe inhaled has been more or less emptied;

FIG. 5 shows the section along line V-V in FIG. 4;

FIG. 6 shows a further illustration corresponding to FIG. 1, this timeduring removal of the closure cap;

FIG. 7 shows the section along line VII-VII in FIG. 6;

FIG. 8 shows the vertical section according to FIG. 1, but followingremoval of the closure cap and the resulting displacement of a meteringchamber into the emptying-standby position;

FIG. 9 shows the section along line IX-IX in FIG. 8;

FIG. 10 shows a detail-view illustration corresponding to FIG. 3,relating to the situation according to FIG. 8;

FIG. 11 shows a follow-up illustration to FIG. 8, but relating to aposition assumed during inhalation;

FIG. 12 shows the section along line XII-XII in FIG. 11;

FIG. 13 shows a further detail-view illustration corresponding to FIG.3, but relating to the situation according to FIG. 11;

FIG. 14 shows a further vertical-section illustration corresponding toFIG. 1, this time relating to an intermediate position as the closurecap is being replaced following completion of inhalation;

FIG. 15 shows a follow-up illustration to FIG. 14, relating to anintermediate position;

FIG. 16 shows a follow-up illustration to FIG. 15, relating to anintermediate position as the operation of screwing on the closure capcontinues;

FIG. 17 shows the cross-section through the metering device in theemptying-standby position along line XVII-XVII in FIG. 8;

FIG. 18 shows the cross-sectional illustration through the meteringdevice along line XVIII-XVIII in FIG. 11;

FIG. 19 shows an illustration which corresponds to FIG. 17 and has beentaken along line XIX-XIX in FIG. 11, relating to the emptying-releaseposition;

FIG. 20 shows the section along line XX-XX in FIG. 11 through thestorage chamber, with the substance which is stored here having beenleft out;

FIG. 21 shows a perspective detail illustration of an inner cylinder ofthe metering device;

FIG. 22 shows a further perspective illustration of the inner cylinder;

FIG. 23 shows a perspective detail illustration of the metering rod ofthe metering device;

FIG. 24 shows a perspective detail illustration of the piston;

FIG. 25 shows a further perspective detail illustration of a rotor-likeblade for disposing on the inner cylinder;

FIG. 26 shows a further perspective illustration of the rotor-likeblade; and

FIG. 27 shows, in a detail drawing, the bottom view of a cover of anannular chamber.

DESCRIPTION OF THE INVENTION

The metering device 1 which is illustrated in the figures and isintended for the inhalation of a pulverulent substance 2, in particulara medicinal substance, is realized as a short-elongate device which canreadily be carried in a pocket and has a cylindrical housing 3 whichdetermines its shape.

The cylindrical, tube-like housing 3 has, at the head end, an outercylinder 4 which can be rotated about the device axis x relative to thehousing 3. This outer cylinder is secured in a rotatable manner on thehousing 3 in the region of an end-side radial step 5.

This likewise cylindrical, tube-like outer cylinder 4 merges, at thehead end of the device 1, into an attached mouthpiece 6 which is formedappropriately for the mouth, for example is flattened. This mouthpiece 6can have a cup-like closure cap 7 engaging over it in a protectivemanner. This closure cap is realized as a screw cap, for which reason anassociated internal thread 8 engages in a corresponding external thread9 on the lateral wall of the housing 3.

The outer cylinder 4 is connected to the closure cap 7 in a rotationallyfixed manner, for which reason the outer cylinder has, on the outside ofits lateral wall, vertically oriented ribs 10 which interact withcorrespondingly positioned, slot-like vertical grooves 11 on the insideof the wall of the closure cap 7. Accordingly, screw-action actuation ofthe closure cap 7 causes the outer cylinder 4 to be rotated about thedevice axis x.

At the foot end, the end periphery of the cup-like closure cap 7 engagesin a stop-limiting manner, and with sealing via a cone, against anannular shoulder 12, which is achieved on account of the abovementionedstep of the cylindrical housing 3.

The closure cap 7 serves, at the same time, as an actuating handle 13for dispensing the pulverulent substance 2 in reproduciblesub-quantities 14, for which purpose use is made of the axialscrew-action displacement provided by the threaded engagement betweenthe internal thread 8 and external thread 9. The substance 2 isaccommodated (possibly such that it can be refilled) in a storagechamber 15 of the housing 3. A metering device conveys a respectivesub-quantity 14 of substance to a transfer location U located outsidethe storage chamber 15.

The meterable substance is a (usually medicinal) pulverulent substance2. It is possible for basic bodies such as lactose, which are capablefor example of transporting a suction stream, to be carriers for finemicronized drug particles adhering to the surface.

The storage chamber 15 is terminated at the bottom by a cup-likepressure-exerting base 16, which is spring-loaded in the direction ofthe mouthpiece 6 by means of a compression spring 17. The compressionspring 17 has its foot-side end turn supported on a base cap 18, whichcloses the housing 3 there. This base cap is in latching engagement withthat portion of the housing 3 which is of larger cross-section here onits inside wall, a corresponding latching collar 19 of the base cap 18engaging in a matching annular groove of the housing 3.

The head-side end turn of the biased compression spring 17 subjects aninner shoulder 20 of a hollow piston 21 of the piston-like means 16/21to loading action. As can be seen from the illustrations, thepressure-exerting base 16, which is in the form of a graduated cup, isconnected with latching action to the hollow piston 21 in the region ofthe inner shoulder 20.

The cup periphery of the pressure-exerting base 16 forms an annular lip22 which, on account of its elastomeric material, strips substance offthe wall of the storage chamber 15 without leaving any residues.

In the exemplary embodiment illustrated, the compression spring 17 is acylindrical spring which, in the state in which it is relieved ofstressing, has a length corresponding approximately to ten times themaximum contact-pressure length. The contact-pressure length is definedby the extent of axial displacement of the pressure-exerting base 16between a lower position according to FIG. 1, this positioncorresponding to the filling position, and an upper, stop-limitedposition of the pressure-exerting base 16 in the storage chamber 15according to FIG. 4. Thus, the exemplary embodiment illustrated providesa contact-pressure length of 15 mm. As a result of the configuration ofthe spring, in particular as a result of the selected length of thespring, the pressure-exerting base 16 is subjected to a constant springpressure over the entire contact-pressure length, and this leads to thesubstance being compressed uniformly throughout the duration of use ofthe device 1.

A hollow upright stub 23 extends centrally from the base cap 18.Together with the hollow piston 21 which encloses it at a distanceapart, this hollow upright stub forms a chamber 24 for the compressionspring 17. The hollow upright stub 23 contains, in its center, amoisture-absorbing material in the form of a drying-agent capsule 25. Atthe transition to the outer cylinder 4, which follows the housing 3 inthe axial direction, the storage chamber 15 terminates with a chamberceiling 26 formed integrally with the lateral wall of the storagechamber 15. Passing through the center of this chamber ceiling is acylinder portion 27 of a rotary part 28 which extends in a planeperpendicular to the device axis x.

This rotary part is of substantially plate-like configuration and isconnected in a rotationally fixed manner to the outer cylinder 4 and,accordingly, can be rotated about the device axis x in relation to thechamber ceiling 26. The cylinder portion 27 extends on the underside ofthe rotary part 28, passing through the chamber ceiling 26. The lowerfree end surface of the cylinder portion 27 is located in the plane ofthat surface of the chamber ceiling 26 which covers the storage chamber15.

The diameter of the through-opening in the chamber ceiling 26 is largerthan the diameter of the cylinder portion 27. A holder, of annular shapein plan view, for a rotor blade R, is positioned in the annular gapwhich remains. This rotor blade is connected in a rotationally fixedmanner to the cylinder portion 27.

The inner surface of the rotor ring 30, this inner surface beingdirected toward the storage chamber 15, is located in the plane of thecorrespondingly directed end surface of the cylinder portion 27.

The rotor R, which is illustrated on its own in FIGS. 25 and 26, carrieson the underside, that is to say in the direction toward the storagechamber 15, a blade 29. This is a blade 29 which is in the form of aspherical-cap portion and projects radially outward beyond the ring 30of the rotor R. The blade 29 correspondingly engages beneath that regionof the chamber ceiling 26 which adjoins the rotor R radially on theoutside, that surface of the blade 29 which is directed toward thechamber ceiling 26 being of planar configuration. This surface of theblade 29 engages against the top surface of the chamber which isdirected toward the blade. The blade 29 extends radially as far as theinner wall of the storage chamber 15. From this radially outer region,the blade 29 slopes up convexly in the radially inward direction, asseen in cross-section, to an axial height corresponding approximately tothe extent by which the blade 29 projects radially beyond the rotor ring30.

As a result of this arrangement, the blade 29 of the rotor R projectsinto the substance stored in the storage chamber 15. The shoulder formedby the chamber ceiling 26, in interaction with the blade 29 or rotor R,which can be rotated relative to the storage chamber 15, forms a statorSt.

The rotor R is clipped on the cylinder portion 27 of the rotary part 28via the rotor ring 30.

The cylinder portion 27 accommodates a sealing bushing 31 in its center.This bushing consists of a rubber material or a similar elasticmaterial. This leaves, in its center, a cross-sectionally slot-likeguide opening 32 for a cross-sectionally adapted metering rod 33.

In the simplest configuration, the sealing bushing 31 and also anannular seal 35 provided between the rotary part 28 and a housingportion 34, which engages over the chamber ceiling 26 on the housingside, may be produced by two-component injection molding together withthe rotary part 28 and, furthermore, with an inner cylinder, which willbe described in more detail. It is also possible in this respect,however, for the rubber or elastomer parts to be provided subsequentlyduring production.

At the foot end, the hollow piston 21, which is connected with latchingaction to the pressure-exerting base 16, has a radial extension arm 36.Integrally formed on the latter is an axially oriented indicatingprotrusion 37 which engages over the storage-chamber wall on itsoutside. The axial position of this indicating protrusion, this positionbeing reached in dependence on the position of the pressure-exertingbase, can be seen by the user from the outside through a viewing window38 provided in the housing. A filling-level indicator 39 is provided asa result.

The metering rod 33 is appropriately configured for functioning as amoving metering chamber 40 for the sub-quantity 14 of substance which isto be dispensed, the metering rod 33 moving linearly along thelongitudinal center axis x-x of the substantially rotationallysymmetrical device 1, and this being accompanied by a rotary movementexecuted about the longitudinal center axis x-x. The metering rod 33 isformed substantially as a flat part with an elongate-rectangularcross-section. The length ratio of narrow side to broad side isapproximately 1:3 in the exemplary embodiment illustrated.

At the end which is directed away from the mouthpiece 6, the meteringrod 33 forms a portion which tapers to a point more or less in themanner of a cross-recessed screwdriver tip. The two mirror-symmetricaloblique flanks here extend from the respective broad sides of themetering rod 33 (cf. FIG. 20).

On account of the metering rod 33 being carried along in rotation, thecross-sectional configuration of the metering rod 33 and the tapering ofthe free end region have a loosening, displacing effect in the centralregion in relation to the mass of pulverulent substance 2.

The metering chamber 40 is realized as a transverse hole which runssubstantially perpendicularly to the longitudinal center axis x-x andhas an axis which passes through the broad-side surfaces of the meteringrod 33. The transverse hole is formed conically, so that the transversehole tapers in the direction of one broad-side surface of the meteringrod 33. Furthermore, as can be seen for example from the illustration inFIG. 2, the metering chamber 40, which is formed in the region of thatend of the metering rod 33 which projects into the mass of substance, isdisposed eccentrically in relation to the broad-side surfaces of themetering rod 33, that is to say it is offset laterally in relation tothe longitudinal axis x-x.

The displacement path of the metering chamber 40, which moves linearly,and, at the same time, in rotation, allows, in both end positions of themetering rod 33, for the cross-section of the guide opening 32 to bekept closed, with metering-chamber-filling scraping or stripping actionover the length of the said opening 32.

The mouthpiece end of the closure cap 7 forms a docking location 41between the metering rod 33 and closure cap 7, this docking locationdisengaging when subjected to overloading. The latching means on theclosure-cap side here is a resilient hook annulus which is formed in theregion of the free end of a hollow cylinder 43 disposed centrally on theunderside of a closure-cap ceiling 42. The corresponding end of themetering rod 33 is rotationally symmetrical in cross-section, adisk-like radial collar 44, furthermore, projecting out in thetransition region from the flat-part portion to the cylindrical endportion. At an axial spacing from this radial collar 44, that end regionof the metering rod 33 which is directed away from the flat part forms alatching head 45. A wasp-waist-like annular groove 46 is formed betweenthis latching head and the radial collar 44. Inwardly directed noses 47of the resilient tongues of the hook annulus engage in this annulargroove. The noses 47 can pass over the latching head 45 in both axialdirections. The latching action may be fairly tight, since it isreleased and reinstated during the screwing-action displacement of thecap.

The central opening 48 of the mouthpiece 6 is formed in the region of adispersing part 49. This dispersing part 49 opens conically outward,that is to say in the direction away from the storage chamber 15, thewall 50 of the dispersing part merging, in the direction toward thestorage chamber 15, into an annular, roof-like ceiling portion 51. Atthe same time, the latter forms the upper end of the outer cylinder 4,which carries the mouthpiece 6.

The central free space created by the dispersing part 49 has the hollowcylinder 43, which carries the noses 47, passing through it centrally inthe cap-closed position. The annular space which forms here between thehollow cylinder 43 and the dispersing-part wall is filled by a furtherdrying-agent capsule 52 in the cap-closed position.

The outer cylinder 4 accommodates an inner cylinder 53, passing throughthe center of which is the metering rod 33 and, in the cap-closedposition, the hollow cylinder 43 belonging to the closure cap. The innercylinder is connected in a rotationally fixed manner to the outercylinder 4.

This inner cylinder 53 is configured substantially as a hollow body andcarries, in its center, an axially displaceable piston 54. The piston 54is guided more or less in the lower half of the inner cylinder 53,directed toward the storage chamber 15, by a cross-sectionally roundguide portion 55.

That portion of the inner cylinder 53 which is directed away from thestorage chamber 15 forms a piston-head displacement region 56 which hasa cross-section larger than that of the guide portion 55 and of whichthe axially oriented wall 57 has radial openings 58, 58′ and 58″. Theseradial openings are in flow connection with a grille-wall portion 59 ofthe outer cylinder.

Formed beneath the grille-wall portion 59, and furthermore at the footend of the guide portion 55 of the inner cylinder, is a radiallyoriented flow channel 60, which likewise opens toward the grille-wallportion 59. This flow channel may also serve as a window for visuallymonitoring the metering rod 33. It opens out into the free space left inthe center by the guide portion 55. Radially opposite the flow channel60, the guide portion 55 is adjoined by an intermediate channel portion61 which, starting from the guide portion 55, and with the inclusion ofan angle of 45° in relation to a plane oriented perpendicularly to theaxis x, slopes up in the direction of the associated wall of the outercylinder 4 in order then to merge, at the end, into an axially directedchannel 62. This channel 62 is formed by an axially oriented, slot-like,radially outwardly opening recess in the lateral surface of the innercylinder. The channel 62 is covered over radially by the associated wallof the outer cylinder 4.

As well as the radial opening 58, which can be seen by way of example inthe sectional illustration in FIG. 1, two further radial openings 58′and 58″ are provided, and these each enclose, as seen in a planeoriented transversely to the axis x, an angle of 90° in relation to thisradial opening 58 and, by virtue of the inner-cylinder wall beingconfigured appropriately, are in direct air-flow connection with thegrille-wall portion 59.

The axially oriented channel 62 has its end which is directed toward themouthpiece 6 opening out into an annular chamber 63. The latter forms avortex chamber. The ceiling 64 of the latter is of cross-sectionallyroof-like configuration and is provided with peripherally extending,projecting wings 65, 66. These engage peripherally against the innerwall of the outer cylinder 4 and, as seen in the circumferentialdirection, leave intermediate spaces 67 between them, through which anair-flow connection is achieved between the annular chamber 63 and afurther annular space 68 left between the dispersing-part ceilingportion 51 and the annular-chamber ceiling 64.

The ceiling 64 is secured on the inside wall of the inner cylinder 53 byan axially directed flange 69.

The base of the annular chamber 63 is formed by an annular collar 70which projects radially outward on the outside wall of the innercylinder 53 at an axial spacing from the wings 65, 66 of the ceiling 64.It is also the case that this annular collar is supported peripherallyon the inside wall of the outer cylinder 4. This annular collar 70 isinterrupted by the axially oriented channel 62. The annular chamber 63is bounded in the radially inward direction by an end-side wall portionwhich belongs to the inner cylinder 53 and serves for latching theceiling 64. The resulting annular-chamber wall is provided withslot-like through-passages 71 in order to provide air-flow connectionbetween the annular chamber 63 and the piston-head displacement region56.

As can furthermore be seen, in particular, from the sectionalillustration in FIG. 18, the outer-cylinder wall is provided, level withthe annular chamber 63, with two diametrically opposite air-inletopenings 72. These open out tangentially into the annular chamber 63,and this, furthermore, predetermines a common flow direction.Accordingly, a sucking-in action through the air-inlet openings 72results in a predetermined air flow in the annular chamber 63. Theaxially oriented channel 62 opens out, as seen in the flow direction,immediately downstream of the mouth of one air-inlet opening 72 in theannular chamber 63, so that the airstream entering into the annularchamber 63 through the axial channel 62 is deflected specifically in thedesired vortexing direction via the air-inlet openings 72.

The wings of the ceiling 64 are of different widths as seen in thecircumferential direction. Thus, two diametrically opposite wings 65 areapproximately three times the width of the rest of the wings 66, as seenin the circumferential direction. One of these broader wings 65 coversover the mouth region of the axial channel 62 into the annular chamber63 and, accordingly, forms a deflecting-wall wing 73 for the suctionairstream entering into the annular chamber 63 through the axial channel62.

As can further be seen, in particular, from the illustration in FIG. 27,the wings 66 extend circumferentially, in the exemplary embodimentdescribed, over an angle β of 15°. The intermediate spaces 67 leftbetween the wings 66 and 65 likewise extend circumferentially over anangle α of 15°, while the peripheral edges of the broader wings 65enclose an angle δ of 45°.

Other distributions are also possible in this respect (for examplesmaller wings—larger intermediate spaces; larger wings—smallerintermediate spaces; irregular configuration of wings and intermediatespaces).

An interrupter 74 is disposed in the annular chamber 63 adjacent to themouth of the axial channel 62 in the annular chamber 63, the interrupterbeing in the airflow direction through the air inlet openings 72. Thisinterrupter limits the circumferential path of the annular chamber 63and accordingly, as a result of this configuration, this path is of aninterrupted form rather than being annular throughout. The rear flank ofthe interrupter 74, this flank being oriented counter to the flowdirection, constitutes a run-on slope 75, connecting the annular-chamberbase to the annular-chamber ceiling, which contains the intermediatespaces 67. This causes the airstream in the end region of the annularchamber 63 to be forcibly deflected axially upward into the furtherannular space 68.

The piston 54, which is retained in a rotationally fixed, but axiallydisplaceable manner, in the inner cylinder 53, has, in first instance, apiston head 76 which opens in disk form in the direction of themouthpiece. This piston head opens conically in cross-section. Twoparallel, axially oriented tongues 77 are integrally formed on theunderside of the piston disk. The piston 54 consist of a rubber-likematerial.

Along their lower free periphery, the tongues 77, which accommodate thecross-sectional contour of the guide portion 55 of the inner cylinder 53on their outside wall, are split in a lip-like manner and, furthermore,in their free peripheral region, they have material-reinforced sealingsurfaces 78.

The flat part of the metering rod 33 is guided between the tongues 77,the sealing surfaces 78, in interaction with the flat part of themetering rod 33, having a stripping and sealing action.

In a basic position of the device according to the illustration in FIG.1, the free peripheries of the tongues 77, these peripheries being splitin a lip-like manner, engage, within an axial depression, against theupper side of the cylinder portion 27.

Furthermore, in this basic position, the disk-like piston head 76 restsin a stop-limited manner on a base region of the piston-headdisplacement region 56. The encircling peripheral region of the free endof the piston head 76 engages with sealing action against the associatedinner wall of the inner cylinder 53.

Furthermore, in this basic position, the head of the metering rod 33,that is to say the radial collar 44 and latching head 45 of the same,rests in the depression created by the disk-like configuration of thepiston head 76.

The piston head 76 here is located at an axial distance beneath theceiling 64.

The device 1 cited functions as follows:

In order to prepare for inhalation, the closure cap 7 is first of allremoved by unscrewing. As the closure cap 7 is being unscrewed upward,the coupling mentioned results in the outer cylinder 4 being carriedalong in rotation and, via this outer cylinder, the inner cylinder 53 aswell as, in the exemplary embodiment cited, all those parts above thestorage-chamber plane which are not connected in a rotationally fixedmanner to the housing 3. Accordingly, the metering rod 33 is alsocarried along in rotation, and furthermore, the action of the closurecap 7 being unscrewed upward gives rise, at the same time, to axialdisplacement of the metering rod 33 via the docking location 41, whichcauses helical displacement of the metering chamber 40 into the as yetclosed emptying-standby position B according to the illustration inFIGS. 6 and 7, in which it is aligned with the flow channel 60.

By virtue of the metering chamber 40 being disposed eccentrically inrelation to the axis of rotation of the metering rod 33, it is filledoptimally as a result of penetrating helically through the mass ofsubstance, assisted by the rotor. The larger-diameter opening surface ofthe metering chamber 40 here is oriented in the direction of rotation.

The simultaneously rotating blade 29 of the rotor R here causes thesurrounding mass of substance to be in a constantly loosened state, ashoveling effect being achieved. When the rotor R rotates in theopposite direction—as the closure cap 7 is screwed on again—the blade 29interacts with the stator St in order to scrape off substance 2 from thesurface of the stator and to press the substance 2 down, as a result ofwhich the mass of substance is evened out. The blade 29 of the rotor R,accordingly, acts on the mass of substance in both directions ofrotation.

When the removal-standby position B of the metering rod 33 is reached,the metering rod is secured with latching action. For this purpose, theradial collar 44 of the metering rod 33 moves behind latching fingers 79which are formed on the underside of the ceiling 64.

As the screwing-action displacement of the closure cap 7 continues, thelatching in the region of the docking location 41 between the hollowcylinder 43 and the metering rod 33 is eliminated. Accordingly, thenoses 47 leave the annular groove 46, whereupon the closure cap 7 can beremoved. The device 1 is now prepared for inhalation.

The screwing-action displacement of the closure cap 7 makes it possibleto provide sufficient force for producing the latching between theradial collar 44 and latching fingers 79 and, furthermore, foreliminating the latching between the latching head 45 and noses 47 onthe cap.

The tongues 77 of the piston 54 cover over the metering chamber 40 oneach side. Accordingly, in this position, it is not possible for thesub-quantity 14 of substance to trickle out even in part. Rather, thesubstance is held reliably captive in the metering chamber 40. Thisprevents cases of double metering when inhalation is not carried out,but the device is closed-up again via the closure cap 7. Furthermore, inthe removal-standby position B of the metering chamber 40, it is alsopossible for the device 1 to be put to one side. Even if the device 1experiences normal kinds of impacts, this does not result in thesub-quantity 14 of substance which is to be inhaled trickling out, whichwould falsify the inhalation result.

The inhalation operation takes place automatically by the usersubjecting the device to suction air, in the simplest case by the userbreathing in.

Air is sucked in via the mouthpiece 6, and this, in first instance, byvirtue of the piston head 76 being subjected to the action of air,results in the piston 54 being displaced axially in the direction of theceiling 64. In the case of the exemplary embodiment illustrated, thepressure required to trigger the device is approximately 2 kgPa.Triggering takes place, as far as possible, in abrupt fashion.

In the raised position, the upper free peripheral region of the pistonhead 76 engages against the underside of an annular wall 80 of theceiling 64. The annular space of the inner cylinder 53 which thenencloses the free peripheral region of the piston head 76 is widenedradially, as a result of which radial flow takes place around the piston54 in the region of the piston head 76. This gives a main airstream awhich flows through the grille-wall portion 59, passing through theradial openings 58, 58′ and 58″, into the piston-head displacementregion 56 and passes, by way of the annular-space region left radiallyoutside the piston head 76, through the openings 71 into the annularchamber 63. Approximately 85 to 90% of the total inhalation air volumeis transported via this air-flow path.

At the same time, via the always open radial air-inlet openings 72, airis sucked in directly into the annular chamber 63, in order topredetermine the vortexing direction in the annular chamber 63.

By virtue of the axially displaced piston 54, the tongues 77 arelikewise displaced axially, in order to release the metering chamber 40.The axial displacement of the piston 54 is assisted by the guide portion55, which accommodates the tongues 77, widening slightly in thedirection of the piston head 76, as a result of which there is areduction in the friction between the tongues 77 and the wall of theguide portion 55. It is also the case that the friction between thetongues 77 and the flat part of the metering rod 33 is minimized, beingon the region of the sealing surfaces 78.

The metering chamber 40 is then located in a removal-release position F,in which it lies freely in the flow path between the flow channel 60 andintermediate channel portion 61. In the exemplary embodimentillustrated, approximately 10 to 15% of the inhalation air volume istransported via this substance-transporting airstream b.

The metering chamber is cleared out with through-suction from the flowchannel 60, this, furthermore, taking place from the smaller openingsurface in the direction of the larger opening surface of the meteringchamber 40. The two-fold deflection through in each case approximately45° into the angled intermediate channel portion 61 and, from thelatter, into the axially oriented channel 62 results, in the manner of abaffle-plate effect, in the initial breaking up of relatively largeparticles of powder, which further leads to an improved inhalationresult.

The substance-laden airstream flowing axially, at relatively high speed,into the annular chamber 63 via the channel 62 is deflected via thedeflecting-wall wing 73 and, assisted by the initial flow by way of theradial air-inlet openings 72, in the circumferential direction.Relatively large particles of powder are further broken up on thisdeflecting-wall wing 73.

As a result of this configuration, the substance-laden airstream isguided outside the piston region. The piston 54 merely has powder-freeair flowing around it.

Optimum distribution of the sub-quantity 14 of substance which is to beinhaled is achieved in the annular chamber 63. The substance-laden airpasses out through the intermediate spaces 67 for inhalation. Relativelyheavy particles of powder which have possibly not been broken up, orhave not been sufficiently broken up, are directed into the annularspace 68 at the latest via the interrupter 74.

In the annular chamber 63, the initially substantially axially inflowingairstreams a and b are directed in a common horizontal direction ofcirculation in order then to pass jointly into the mouthpiece 6, withaxial passage through the ceiling 64.

A number of features are provided in order to indicate successfulinhalation to the user. In first instance, a visual check can be carriedout in that the piston 54, once raised by suction air, is retained inits raised position on account of the, albeit low, frictional forcespresent. The piston 54, or the tongues 77 thereof, can be seen in theremoval-standby position B through the radially outwardly open flowchannel 60. This can be further assisted by the tongues 77 beingconspicuously colored. Once inhalation has taken place and the piston 54has been raised correspondingly, the tongues 77 cannot be seen. Rather,there is a free view of the empty metering chamber 40. It is also thecase that the action of the piston 54 striking against the underside ofthe sealing 64 can be sensed both acoustically and by touch.

Once inhalation has taken place, and alternatively also if it is notdesired to effect inhalation from the removal-standby position B, theclosure cap 7 is screwed on again, the latching between the radialcollar 44 and the latching fingers 79 being eliminated in first instanceby virtue of the latching head 45 being acted upon by the noses 47. Theretaining forces of this latching connection are of a correspondinglysmaller magnitude than the amount of force which is necessary fordeflecting the noses 47. As the action of screwing the closure cap 7downward continues, the radial collar 44 on the metering rod displacesthe piston 54 back again into its basic position. At the same time, withaxial displacement and corresponding rotary movement, the metering rod33 is displaced downward into the storage chamber. The action of thepiston 54 being displaced back via the metering rod 33 terminates withthe free ends of the tongues 77, which are formed in the manner of lips,striking against the facing ceiling surface of the cylinder part 27. Asthe downward-screwing displacement continues, finally the noses 47 enterinto the annular groove 46 of the metering rod 33. This final latchingaction is discernable to the user acoustically and by touch, to indicatethat the closing operation is at an end. It is thus also ensured that alatching action between the metering rod 33 and closure cap 7 whichcauses the metering rod 33, and thus the metering chamber 40, to becarried along into the removal-standby position B is only achieved inthe lowermost position of the metering rod 33, in which position themetering chamber 40 is filled. Accordingly, there is always a filledmetering chamber 40 available when the metering rod 33 is raised.

Incorrect operation is reliably avoided. Improper closure of the device1 means that, during the next attempt at inhalation, the metering rod33, which has accordingly not been raised, on one hand closes thepassage between the flow channel 60 and intermediate channel portion 61by way of its flat-part portion. It is also the case that the meteringrod 33 continues to act on the associated surface of the piston head 76via the radial collar 44. Accordingly, when an attempt is made atinhalation, the closure of the flow channel 60 and the blocking of thepiston 54 means that it is not possible to build up any air flow (withthe exception of the small amount of flow via the small radial air-inletopenings 72). This clearly signals incorrect positioning to the user.This can only be eliminated by the device 1 being properly closed.

All features disclosed are (in themselves) pertinent to the invention.The disclosure content of the associated/attached priority documents(copy of the prior application) is hereby also included in full in thedisclosure of the application, also for the purpose of incorporatingfeatures of these documents in claims of the present application.

List of Reference Signs

-   1 Device-   2 Substance-   3 Housing-   4 Outer cylinder-   5 Radial step-   6 Mouthpiece-   7 Closure cap-   8 Internal thread-   9 External thread-   10 Ribs-   11 Grooves-   12 Annular shoulder-   13 Actuating handle-   14 Sub-quantity of substance-   15 Storage chamber-   16 Pressure-exerting base-   17 Compression spring-   18 Base cap-   19 Latching collar-   20 Inner shoulder-   21 Hollow piston-   22 Annular lip-   23 Upright stub-   24 Spring chamber-   25 Drying-agent capsule-   26 Chamber ceiling-   27 Cylinder portion-   28 Rotary part-   29 Blade-   30 Rotor ring-   31 Sealing bushing-   32 Guide opening-   33 Metering rod-   34 Housing portion-   35 Annular seal-   36 Radial extension arm-   37 Indicating protrusion-   38 Viewing window-   39 Filling-level indicator-   40 Metering chamber-   41 Docking location-   42 Closure-cap ceiling-   43 Hollow cylinder-   44 Radial collar-   45 Latching head-   46 Annular groove-   47 Noses-   48 Mouthpiece opening-   49 Dispersing part-   50 Wall-   51 Ceiling portion-   52 Drying-agent capsule-   53 Inner cylinder-   54 Piston-   55 Guide portion-   56 Piston-head displacement region-   57 Region wall-   58 Radial opening-   58′ Radial opening-   58″ Radial opening-   59 Grille-wall portion-   60 Flow channel-   61 Intermediate channel portion-   62 Channel-   63 Annular chamber-   64 Ceiling-   65 Wing-   66 Wing-   67 Intermediate spaces-   68 Annular space-   69 Flange-   70 Annular collar-   71 Openings-   72 Air-inlet openings-   73 Deflecting-wall wing-   74 Interrupter-   75 Run-on slope-   76 Piston head-   77 Tongues-   78 Sealing surfaces-   79 Latching finger-   80 Annular wall-   x Device axis-   B Removal-standby position-   F Removal-release position-   R Rotor-   St Stator-   U Transfer location-   α Angle of intermediate spaces 67-   β Angle of wings 66-   δ Angle of wings 65-   a Main airstream-   b Substance-transporting airstream

The invention claimed is:
 1. A metering device which can be activated bya user's suction airstream and intended for an inhalation of apulverulent substance, including a medicinal substance, the meteringdevice comprising: a piston slidably engaged with a metering rod, thepiston having a disk-shaped upper region with tongues extending from anunderside of the disk-shaped region; a mouthpiece; and a storage chamberfor storing the pulverulent substance; wherein the metering rod has ametering chamber configured to move a portion of the pulverulentsubstance out of said storage chamber into an emptying-standby position;and wherein the tongues cover and close the metering chamber when themetering chamber is in the emptying-standby position and thenrelease/open the metering chamber when the piston is displaced by theuser's suction airstream.
 2. The metering device according to claim 1,further comprising an annular chamber having an annular wall, andwherein in an upper end position, an upper periphery of said pistonengages in front of said annular wall.
 3. The metering device accordingto claim 2, wherein said annular chamber has a ceiling with peripherallyextending, projecting wings which leave intermediate spaces betweenthem.
 4. The metering device according to claim 3, further comprising aninclined deflecting wall disposed above said ceiling of said annularchamber.
 5. The metering device according to claim 3, wherein part ofsaid projecting wings is of a relatively wide configuration in acircumferential direction, in order to form a deflecting-wall wing forthe suction airstream.
 6. The metering device according to claim 3,wherein: said ceiling has latching fingers formed thereon; and saidmetering rod has a radial collar which moves behind said latchingfingers.
 7. The metering device according to claim 2, furthercomprising: an axially running channel having a closure cap, saidaxially running channel extending from an emptying side of said meteringchamber and terminates in said annular chamber; an inner cylinder havinga lateral-wall side and being moved by said closure cap; and adeflecting-wall wing provided for deflecting an axial airstreamdirection into a circumferential plane and disposed on said lateral-wallside.
 8. The metering device according to claim 7, further comprisingtwo air-flow paths including a first air-flow path opening into theemptying-standby position of said metering chamber and a second air-flowpath leading directly into said annular chamber disposed upstream ofsaid mouthpiece and where both said air-flow paths meet.
 9. The meteringdevice according to claim 8, further comprising a grill-wall portion andone of said air-flow paths is sucked in through said grille-wallportion.
 10. The metering device according to claim 8, furthercomprising an outer cylinder having an air-inlet grille surface disposedon that side of said metering rod which is disposed opposite to anemptying direction of said metering chamber.
 11. The metering deviceaccording to claim 10, further comprising a flow channel directed towardsaid metering chamber and disposed beneath said air-inlet grillesurface, level with a position assumed by said metering chamber in theemptying-standby position.
 12. The metering device according to claim10, wherein said inner cylinder has an interior available entirely for afree distribution of air sucked in through said air-inlet grillesurface, and it is in flow connection with said annular chamber.
 13. Themetering device according to claim 10, wherein said outer cylinder has alateral wall with two radially opposite air-inlet openings formedtherein.
 14. The metering device according to claim 13, wherein saidair-inlet openings open out in a tangentially directed manner into saidannular chamber, a common flow direction being predetermined in theprocess.
 15. The metering device according to claim 10, wherein saidouter cylinder has a lateral wall with at least one air-inlet openingformed therein.
 16. The metering device according to claim 8, whereinsaid storage chamber has a storage-chamber wall with an inwardlydirected stator-shaped shoulder; and further comprising a rotor-shapedblade disposed in a region of an upper layer of the pulverulentsubstance stored in said storage chamber, said rotor shaped blade isclipped in on a lower periphery of said inner cylinder, and it interactswith said inwardly directed stator-shaped shoulder of said storagechamber wall and is in contact with said inwardly directed stator-shapedshoulder.
 17. The metering device according to claim 1, wherein: saidpiston has an upper depression formed therein; and aid metering rod hasa latching head being at least partially sunken into said upperdepression of said piston.
 18. The metering device according to claim 1,wherein along their lower free periphery, said tongues are split in alip-shaped manner in order to achieve a clamping action.
 19. Themetering device according to claim 1, wherein said tongues havematerial-reinforced sealing surfaces.
 20. The metering device accordingto claim 1, further including a channel in alignment with said meteringchamber, in an as yet closed removal standby position said channel isdirected toward one of said tongues, to allow a visual check.
 21. Themetering device according to claim 1, wherein said storage chamber has astorage-chamber wall; and further comprising an indicator disposed in aregion of said storage-chamber wall for indicating an actual fillinglevel.
 22. The metering device according to claim 21, further comprisinga metering-chamber piston and an upward movement of saidmetering-chamber piston is stopped.
 23. The metering device according toclaim 1, further comprising: an inhaler having two end regions; and twodrying-agent capsules disposed in said two end regions of said inhaler.24. The metering device according to claim 1, wherein said metering rodis latched in a disengageable manner in an upper position.
 25. Themetering device according to claim 1, wherein said metering chamber isone of a plurality of metering chambers.